Good points,

I can tell you of a guy I knew that was a certified mechanic and a die hard quaker state user until one day. His beloved 65 corvette needed a new intake gasket. Upon removal of the intake, the oil valley was so full of sludge you could not see the lifters or hardly the pushrods. This was all from quaker state. I know some of you will say "how often did he change his oil, etc." This guy was a stickler and the corvette was mint. So that oil blows plain and simple. Have they changed it over the years? Maybe, but I would still stay away from it. If you cannot afford good oil like mobil 1, then you probably don't need a mercedes.